Milkweed (Asclepias). Didn’t see the plant in flower, so I can’t say which species. October 28, Shenandoah National Park, parking lot at Riprap Hollow trailhead.
closeup of seeds
unripe pods not quite ready
fly! be free!
I just love how they form little balloons as they’re getting ready to go…
…and embrace the sky
Asclepias syriaca; Asclepiadaceae (milkweed family)
Click on the picture below to enlarge and check out all the tiny moths! 
There are a whopping 72 native species of Asclepias found all over the US and Canada. About a dozen of them are in the mid-Atlantic.
Closeup of two individual flowers:
Mug shot:
This is a big plant – up to six feet – with big leaves and big, showy, fragrant flowers heads, each of which can bear up to 120 individual flowers. It’s good for attracting butterflies but beware if you want it in your garden: because it spreads vigorously by roots, it’s considered a weed in much of its range. The USDA site has a great document about the plant, including interesting ethnobotanical history. Tomorrow, another type of milkweed.
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